View Source imglab

imglab is the official Elixir library to integrate with imglab services.

installation

Installation

Add imglab to your list of dependencies in mix.exs:

def deps do
  [
    {:imglab, "~> 0.2"}
  ]
end

And run:

$ mix deps.get

elixir-compatibility

Elixir compatibility

imglab has been successfully tested on the following Elixir versions: 1.13, 1.12, 1.11, 1.10, 1.9, 1.8, 1.7, 1.6, 1.5, and 1.4.

generating-urls

Generating URLs

You can use Imglab.url/3 function to generate imglab compatible URLs for your application.

The easiest way to generate a URL is to specify the source_name, path and required parameters:

Imglab.url("assets", "image.jpeg", width: 500, height: 600)
"https://assets.imglab-cdn.net/image.jpeg?width=500&height=600"

Imglab.url("avatars", "user-01.jpeg", width: 300, height: 300, mode: :crop, crop: :face, format: :webp)
"https://avatars.imglab-cdn.net/user-01.jpeg?width=300&height=300&mode=crop&crop=face&format=webp"

If some specific settings are required for the source you can use a Imglab.Source struct instead of a string source name:

Imglab.url(Imglab.Source.new("assets"), "image.jpeg", width: 500, height: 600)
"https://assets.imglab-cdn.net/image.jpeg?width=500&height=600"

using-secure-image-sources

Using secure image sources

For sources that require signed URLs you can specify secure_key and secure_salt attributes:

"assets"
|> Imglab.Source.new(secure_key: "assets-secure-key", secure_salt: "assets-secure-salt")
|> Imglab.url("image.jpeg", width: 500, height: 600)
"https://assets.imglab-cdn.net/image.jpeg?width=500&height=600&signature=generated-signature"

signature query parameter will be automatically generated and attached to the returned URL.

Note: secure_key and secure_salt attributes are secrets that should not be added to a code repository. Please use environment vars or other secure method to use them in your application.

using-http-instead-of-https

Using HTTP instead of HTTPS

In the case that HTTP schema is required instead of HTTPS you can set https attribute to false when creating the source:

"assets"
|> Imglab.Source.new(https: false)
|> Imglab.url("image.jpeg", width: 500, height: 600)
"http://assets.imglab-cdn.net/image.jpeg?width=500&height=600"

Note: HTTPS is the default and recommended way to generate URLs with imglab.

specifying-parameters

Specifying parameters

Any parameter from the imglab API can be used to generate URLs with Imglab.url/3 function. For parameters that required dashes characters like trim-color you can use regular underscore Elixir atoms like :trim_color those will be normalized in the URL generation to it's correct form:

Imglab.url("assets", "image.jpeg", trim: "color", trim_color: "black")
"https://assets.imglab-cdn.net/image.jpeg?trim=color&trim-color=black"

It is possible to use quoted atoms too:

Imglab.url("assets", "image.jpeg", trim: "color", "trim-color": "black")
"https://assets.imglab-cdn.net/image.jpeg?trim=color&trim-color=black"

specifying-color-parameters

Specifying color parameters

Some imglab parameters can receive a color as value. It is possible to specify these color values as strings:

# Specifying a RGB color as string
Imglab.url("assets", "image.jpeg", width: 500, height: 600, mode: :contain, background_color: "255,0,0")
"https://assets.imglab-cdn.net/image.jpeg?width=500&height=600&mode=contain&background-color=255%2C0%2C0"

# Specifying a RGBA color as string
Imglab.url("assets", "image.jpeg", width: 500, height: 600, mode: :contain, background_color: "255,0,0,128")
"https://assets.imglab-cdn.net/image.jpeg?width=500&height=600&mode=contain&background-color=255%2C0%2C0%2C128"

# Specifying a named color as string
Imglab.url("assets", "image.jpeg", width: 500, height: 600, mode: :contain, background_color: "red")
"https://assets.imglab-cdn.net/image.jpeg?width=500&height=600&mode=contain&background-color=red"

# Specifying a hexadecimal color as string
Imglab.url("assets", "image.jpeg", width: 500, height: 600, mode: :contain, background_color: "F00")
"https://assets.imglab-cdn.net/image.jpeg?width=500&height=600&mode=contain&background-color=F00"

You can additionally use Imglab.Color macros to specify these color values:

# Remember to import Imglab.Color before use these macros
import Imglab.Color

# Using color macro for a RGB color
Imglab.url("assets", "image.jpeg", width: 500, height: 600, mode: "contain", background_color: color(255, 0, 0))
"https://assets.imglab-cdn.net/image.jpeg?width=500&height=600&mode=contain&background-color=255%2C0%2C0"

# Using color macro for a RGBA color
Imglab.url("assets", "image.jpeg", width: 500, height: 600, mode: "contain", background_color: color(255, 0, 0, 128))
"https://assets.imglab-cdn.net/image.jpeg?width=500&height=600&mode=contain&background-color=255%2C0%2C0%2C128"

# Using color macro for a named color
Imglab.url("assets", "image.jpeg", width: 500, height: 600, mode: "contain", background_color: color("red"))
"https://assets.imglab-cdn.net/image.jpeg?width=500&height=600&mode=contain&background-color=red"

Note: specify hexadecimal color values using Imglab.Color macros is not allowed. You can use strings instead.

specifying-position-parameters

Specifying position parameters

Some imglab parameters can receive a position as value. It is possible to specify these values using strings:

# Specifying a horizontal and vertical position as string
Imglab.url("assets", "image.jpeg", width: 500, height: 500, mode: "crop", crop: "left,top")
"https://assets.imglab-cdn.net/image.jpeg?width=500&height=500&mode=crop&crop=left%2Ctop"

# Specifying a vertical and horizontal position as string
Imglab.url("assets", "image.jpeg", width: 500, height: 500, mode: "crop", crop: "top,left")
"https://assets.imglab-cdn.net/image.jpeg?width=500&height=500&mode=crop&crop=top%2Cleft"

# Specifying a position as string
Imglab.url("assets", "image.jpeg", width: 500, height: 500, mode: "crop", crop: "left")
"https://assets.imglab-cdn.net/image.jpeg?width=500&height=500&mode=crop&crop=left"

You can additionally use Imglab.Position macros to specify these position values:

# Remember to import Imglab.Position before use these macros
import Imglab.Position

# Using position macro for a horizontal and vertical position
Imglab.url("assets", "image.jpeg", width: 500, height: 500, mode: "crop", crop: position("left", "top"))
"https://assets.imglab-cdn.net/image.jpeg?width=500&height=500&mode=crop&crop=left%2Ctop"

# Using position macro for a vertical and horizontal position
Imglab.url("assets", "image.jpeg", width: 500, height: 500, mode: "crop", crop: position("top", "left"))
"https://assets.imglab-cdn.net/image.jpeg?width=500&height=500&mode=crop&crop=top%2Cleft"

# Using position macro for a position
Imglab.url("assets", "image.jpeg", width: 500, height: 500, mode: "crop", crop: position("left"))
"https://assets.imglab-cdn.net/image.jpeg?width=500&height=500&mode=crop&crop=left"

specifying-url-parameters

Specifying URL parameters

Some imglab parameters can receive URLs as values. It is possible to specify these parameter values as strings.

Imglab.url("assets", "image.jpeg", width: 500, height: 600, watermark: "logo.svg")
"https://assets.imglab-cdn.net/image.jpeg?width=500&height=600&watermark=logo.svg"

And even use parameters if required:

Imglab.url("assets", "image.jpeg", width: 500, height: 600, watermark: "logo.svg?width=100&format=png")
"https://assets.imglab-cdn.net/image.jpeg?width=500&height=600&watermark=logo.svg%3Fwidth%3D100%26format%3Dpng"

Additionally you can use nested Imglab.url/3 calls to specify these URL values:

Imglab.url(
  "assets",
  "image.jpeg",
  width: 500,
  height: 600,
  watermark: Imglab.url("assets", "logo.svg", width: 100, format: "png")
)
"https://assets.imglab-cdn.net/image.jpeg?width=500&height=600&watermark=https%3A%2F%2Fassets.imglab-cdn.net%2Flogo.svg%3Fwidth%3D100%26format%3Dpng"

If the resource is located in a different source we can specify it using Imglab.url/3:

Imglab.url(
  "assets",
  "image.jpeg",
  width: 500,
  height: 600,
  watermark: Imglab.url("marketing", "logo.svg", width: 100, format: "png")
)
"https://assets.imglab-cdn.net/image.jpeg?width=500&height=600&watermark=https%3A%2F%2Fmarketing.imglab-cdn.net%2Flogo.svg%3Fwidth%3D100%26format%3Dpng"

Using secure sources for URLs parameter values is possible too:

marketing_source = Imglab.Source.new("marketing", secure_key: "marketing-secure-key", secure_salt: "marketing-secure-salt")

Imglab.url(
  "assets",
  "image.jpeg",
  width: 500,
  height: 600,
  watermark: Imglab.url(marketing_source, "logo.svg", width: 100, format: "png")
)

signature query parameter will be automatically generated and attached to the nested URL value.

generating-urls-for-on-premises-imglab-server

Generating URLs for on-premises imglab server

For on-premises imglab server is possible to define custom sources pointing to your server location.

  • :https - a boolean value specifying if the source should use https or not (default: true)
  • :host - a string specifying the host where the imglab server is located. (default: imglab-cdn.net)
  • :port - a :inet.port_number specifying a port where the imglab server is located.
  • :subdomains - a boolean value specifying if the source should be specified using subdomains instead of using the path. (default: true)

If we have our on-premises imglab server at http://my-company.com:8080 with a source named images we can use the following source settings to access a logo.png image:

"images"
|> Imglab.Source.new(https: false, host: "my-company.com", port: 8080)
|> Imglab.url("logo.png", width: 300, height: 300, format: "png")
"http://images.my-company.com:8080/logo.png?width=300&height=300&format=png"

It is possible to use secure sources too:

"images"
|> Imglab.Source.new(https: false, host: "my-company.com", port: 8080, secure_key: "images-secure-key", secure_salt: "images-secure-salt")
|> Imglab.url("logo.png", width: 300, height: 300, format: "png")
"http://images.my-company.com:8080/logo.png?width=300&height=300&format=png&signature=generated-signature"

using-sources-with-disabled-subdomains

Using sources with disabled subdomains

In the case that your on-premises imglab server is configured to use source names as paths instead of subdomains you can set subdomains attribute to false:

"images"
|> Imglab.Source.new(https: false, host: "my-company.com", port: 8080, subdomains: false)
|> Imglab.url("logo.png", width: 300, height: 300, format: "png")
"http://my-company.com:8080/images/logo.png?width=300&height=300&format=png"

license

License

imglab source code is released under MIT License.